Telephone system



Jan. 5, 1932. J. I. BELLAMY 1,839,450

TELEPHONE SYSTEM Filed March 17, 1928 3 Sheets-Sheet 1 Jan. 5, 1932. J.l. BELLAMY 1,839,460

TELEPHONE SYSTEM Filed March 17, 1928 s Sheets-Sheet 2 J: 1111 BellamyJan 5, 1932. J. 1- BELLAM Y 7 1,339,450

TELEPHONE SYSTEM Filed March 17, 1928 3 Sheets-Sheet 3 John I. Bellamy MM- Patented Jan. E5, 1 9 32- UNITED srAras PATENT OFFIECE JOHN I.BELLALIY, OF BROOKFIELD, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TOASSOCIATED ELECTRIC LABORATORIES, INC., OF CHICAGO, ILLINOIS, ACORPORATION OF DELAWARE TELEPHONE SYSTEM Application filed March 17,1928.

The present invention relates to telephone systems in general, but isconcerned more particularl with automatic telephone systems employmgregister senders, although certain of its features are not confinedspecifically thereto.

One object is the production of new and improved circuit arrangementswhereby the setting of the translator switch in a register sender underthe control of registering apparatus is accomplished in accordance withconnections common to a plurality of register translators, therebyavoiding the necessity of providing special cross connections in eachindividual register sender set.

It is a further object of the invention to provide circuit arrangementswhereby the operation of the translator switch may be carried on insuccessive stages as the digits to be translated are received so as toenable the translating switch to complete its hunting operation morequickly following the receipt of the last digit to be translated.

A further object of'the invention is the production of arrangements forautomatically dvancing the translating switch through spar positions towhich no offices have been assigned, and for preventing the translatingswitch from stopping in any one of these spare positions responsive toany possible setting of the registering apparatus.

A further object of the invention is the production of suitablearrangements for performing a special operation, which consists infreeing the register sender and giving the calling subscriber a specialtone when he sets the office-registering apparatus into a position whichdoes not correspond to any assigned oflice.

A further object of the invention is product-ion of a new and improvedrelay arrangement for generating accurately-timedimpulses, which devicemay be readily adjusted so as to give a greater or a lesser time duringan impulse cycle, and which may be separately adjusted to secure thedesired ratio between the closed and open portion of a complete impulsecycle.

A further object of the invention is the production of a new andimproved impulse cor- Serial No. 262,575.

recting repeater which will receive impulses I pulses of a xedpro-determined length. A

special feature of the new impulse correcting device is that the lengthof the impulse which it sends out is not readily susceptible to changesin the voltage of the battery from a which it obtains its operatingcurrent.

Another object is the production of a new and improved switch-controlcircuit, to be used in the switches operated by the register senders,which makes use of windings on the control relays for securing theirslow action instead of the usual copper collars, thereby enabling therelays to become saturated more quickly upon energization.

A further object is the production of a new and improved-trunkingarrangement for using a plurality of levels per group at selectors thathave only a few outgoing trunk groups, thereby decreasing the trafiicper selector per level so as to enable trunk economy to be effectedowing to the increased multiplying flexibility.

Other objects and features, for the most part more or less incidental tothe foregoing, will appear upon a further perusal of the specificationin connection with the accompanying drawings comprising Figures 1-4.

Referring now to the drawings, they show by means of the usual circuitdiagrams a sufficient amount of apparatus in a telephone systemembodying features of the invention to enable the invention to beunderstood. Fig. 1 is a schematic diagram indicating how two shelves often selectors each with their wipers suitably readjusted may bemultiplied together and with other selectors in order to form aflexibleand economical trunking arrangement. Figs. 2-4 show a complete registersender and a part of a switch train with which the register senderco-operates to extend connections.

In Fig. 2 there is shown a selector S (alsoindicated in Fig. 1) havingaccess to two groups of trunk lines, one trunk line of each groupbeingshown. The trunk circuit TC is inserted in the'trunk linecomprising conductors 201203 extending to the selector S andhasassociated therewith the registerthe usual release relay and theusual switch-:

ing relay of the trunk circuit preceding the firlst selector have beencombined into a single ter sender, to ether with the common intermediated1str1 uting frame I. D. F., 4, which is common to a plurality of rester senders. The apparatus shown in comprises the re 'sters A, B, G forrelgistering the three initial letters of calle oflic names, thethousands /hundreds, tens, and units registersfor registering thesubscriber digits in called numbers, the sending switch, and the relays311-315. g

The portion of he director shown in Fig. 4 includes the input controlswitch having wipers 411 and 412, the output control switch havingwipers 404 and 405, the impulse generating and correctin relays 406-409,the translating switch T and the associated relays401, 402,414, 415,439,and 443-445. 80 As is explained in the detailed description of theoperation hereinafter given, the translator switch TS, Fi 4, is arrangedto be set under the control 0 the registers A, B, and C, Fig. 3, intoany one of as many positions zli'as'there are ofiices in the system. Thetranslator switch TS is a testing switch having the wipers 431 to 437shown in the drawings and arranged to be rotated in a forward directiono 3 over bank contacts which may be arrange in a substantialsemi-circle,.as in the 'case of a regular rotary lineswitch. The arranement hereinafter described for settin t e translator switch TS into adesired position may be considered an improvement on the arrangementshown in Fi 6 of the Gillings Patent 1,705,462, issued arch 12, 1929,wherein the hunting switch HS is controlled by the three office-digitregisters 0C 0G and 0G, to advance it to a position depend' g upon thecomposite setting of these three registers.

The number of contact sets in the bank of the translator switch TS maybe from 25 to 100, depending u on the number of oifices in the systeminwhich the register sender'is installed. Ordinarily, the translatorswitch TS has more contact sets than there are oflices, thereby allowingfor the addition of new offices as the telephone system expands. Onespare set of contacts, reserved for future of- =fioe expansion, is shownin Fig. 4.

Since each of the registers A, B, and C of Fig. 3 have ten off-normalpositions, these three registers can be set in any one of one 65thousand separate combinations. Accordinga callin subscriber improperlyoperates his a, I Figs. 3 and 4 taken together show the regising lineand places ground at i 1y, it may happen occasionall that the registersare set n accordance wit a combination not assigned to any ofiice, asfor example when calling evice. For this reason, the upper set ofcontacts shown amociated with the transtion of calls wherein anunassigned ofiice designation is received, as will be explained indetail hereinafter.

The apparatus having been described in general, a detailed descriptionof its operation will now be given. For this purpose it will be assumedthat the trunk line comprising conductors 201-203, Fig. 2, is seizedincidental to a call to a line te'rminatingin the oflice whosedesignating digits corresponding to the three initial letters of itsname, are 3, 4, and 2.

When the trunk line is seized, the conductors of the calling line areextended to conductors 201 and 203, whereupon line relay 204 of thetrunk circuit TC operates over the call- Rmiddle upper armature onrelease trunk conductor 202 so as to maintain the connection and torender the trunk line busy. At its inner upper armature relay 204 closesa circuit for relay 206 andstepping magnet 207 of the registerselectingswitch RSS in series, and at its upper armature it connects test wiper209 of the switch RSS to the junction of stepping magnet 207 and relay206. As a result, relay 206 is short circuited and stepping magnet 207is operated by a ground potential in case the register sender on whichthe wipers of the switch R SS are standing. is busy. Operating magnet207 operates through its self-interrupting contacts and. advances thewipers 208-211 step by step in search of an idle register sender.Assuming that the register sendershown in Figs. 3 and 4 and reached overconductors 212-215 is the first one found'to be idle, the wipers of theswitch RSS come .to rest when they reach the bank no contacts associatedwith this register sender, due to the absence of ground potential on.conductor 213. At this point, relay 206, being no longer shortcircuited, operates in series with magnet 207. Magnet 207 does notoperate at this time due to-the relatively high resistance of relay 206.Upon operating, relay 206 places a multiple ground connection onrelease-trunk conductor 202 at its upper armature so as to maintain thetrunk no line guarded during the impulsing action of line relay 204,which is subsequently to take place; it opens a point in the testcircuit and grounds wiper 209 at its inner upper armature therebygrounding conductor 213 so as to guard the seized register sender; andat its remaining armatures it connects up wipers 208, 210, and 211.

Line relay 221 of the selector S now pulls up over conductors 214 and215 and wipers 210 9 v 4 and of the registers in Fig. 3.

circuit for relay 222 through the upfier winding of series relay-223 andvertica magnet 226. Relay 222 operates in this circuit but rela 223 doesnot operate due tothe rela tive y high resistance of relay 222. -'Ver-'tical magnet 226 fails to operate for the same reason. It will be notedthat while the contacts of relay 221 are in mid position there is ashunt around the high resistance relay 222 through the lower resistancewinding of relay 223. Relay 223 and vertical magnet 226 would operate asa'result of-this condition except for the factthat the condition 6exists during only an extremely short time as the contacts pass from oneposition to another. Upon operating, relay 222 makes a multiple groundconnection to release trunk conductor 202 at its upper armature, and atits lower armature it opens a point in the circuit of release magnet 227and locks itself to battery through the vertical magnet 226, therebyshunting the upper winding of relay 223.

In the register sender, release rela 312 Fig. 3operates over releasetrunk con uctor 213 when the said conductor is grounded as abovedescribed, and prepares the register senderfor operation by ungroundingrestoring conductors 302 and 304 of the output control switch in Fig. 4and release conductor 306 of the input control switch of Fig.

When the calling subscriber dials the first oiiice digit 3, line relay204 of the trunk circuit TC falls back three times momentarily. Eachtime it falls back, relay 204' opens the circuit ofslow'acting relay 206at its inner upper armature, but relay 206 is sufliciently slow torelease that it remains operated throughout the series of impulses. As afurther result of each deenergization of relay 204, a circuit is closedat the lower armature of the relay, through the lower contacts ofrelay206, wiper 208, conductor 212, series relay 415, Fig. 4, wiper 412and the bank contact on which it is standing, and the as sociatedconductor to the operating magnet of the register A, Fig. 3. In responseto the three impulses received over the above traced circuit, theoperating magnet of register A advances,-the wiper of the register threesteps into engagement with the third off-normal bank contact. Seriesrelay 415, Fig. 4, operateswhen the first impulse current is transmittedthrough it, and, being slow acting, remains operated throughout thedigit. Upon operating, relay 415 operates the slow acting relay 414,with the result that a circuit is closed, when relay 415 fallsback,through contacts of relay 414 for operating magnet 410 of theinput-control switch. This circuit is opened a moment later when slowacting relay 414 falls back again. Wiper 412, on advancing from itsfirst contact'to its second contact responsive V tothe operation ofmagnet 410, 'sh1'fts'" the impulse. conductor from the operating magthetranslating switch may start in a manner to be subsequently described.

When the second ofiice digit 4 is dialled, the four impulses aretransmitted over a circuit as hereinbefore traced to wiper 412 and thenby way of the second back contact thereof to the operating magnet ofregister B, Fig. 3, whereupon the wiper of register B is set. inaccordance with the digit 4.

The input control switch of Fig. 4 advances axther step followingreceipt of the second o co digit with the result that the third digit isdirected to the operating magnet of the register C, which registerrecords *the third otfice digit 2. In a similar way, the

' wiper 412 lands on a dead contact and the wipers remain in thisposition until the register sender is released.

Returning now to the point at which relay 443 is first operated at theend of the registration of the first oflice digit due to the advance ofwiper 411 of the output control switch relay 443 connects up relay 442to the wiper oi register A at its upper armature, and at its lowerarmature it prepares a circuit for operating magnet 438 of: translatorswitch TS. At this point it may be pointed out that the circles to theleft of the tapped battery, lo cated to the left of the intermediatedistributing frame IDF and numbered 1 to 11, represent terminals towhich other terminals represented by similarly numbered circles in Fig.3 are to be connected. The interconnecting conductors have been omittedin the drawings in order to avoid undue complication and to render thedrawing easier to fol- Assuming now that wiper 437 is standing on a bankcontact cross connected to some battery tap other than No. 3,.relay 442operates due to the difference in potential at its two terminals andcloses a circuit for stepping relay 439. Relay 439 operates and closes alocking circuit for itself at its inner upper armature through contactsof crating magnet 438. Relay 439 alsocloses a circuit for operatingmagnet 438 at its lower armature and at its three upper armatures itdisconnects relays 440-442 so as to prepare for the next step. Relay 442falls back. When the operating magnet; 438 has completed its stroke, itopens the circuit of relay 439, .whereupon relay 439 falls back andopens the circuit of the operating magnet, at the same time connectingup relays 440-442 again. When the circuit of the operating magnet isopened, the magnet falls back and advances the wipers 431-437 one step.If the potential new placed on the left hand terminal of relay 442through wiper 437 of the translating switch and the bank contact onwhich it is standing is difierent than the potential placed on the righthand terminal of the relay, the relay operates again, whereupon thetranslating switch is advanced another step.

When the wipers of the translating switch arrive upon the contactsassigned to an office whose first digit is 3, relay 442 fails to operateagain because the same potential is now on both terminals, and thetranslating switch remains inert until the second digit is dialled,

as hereinbefore described, whereupon relay 444 is included in thecircuit in series with relay 443 when Wiper 411 of the input controlswitch advances to its third contact at the end of the second digit.Relay 444 connects up test relay 441 to the wiper of register B, Fig. 3,with the result that relay 441 operates and closes a circuit forstepping relay 439 to bring about a further advance of the switch,

in case the potential encountered by wiper 436 of the translator switchTS and placed on the left hand terminal of the relayis unlike apotential previously placed on the right hand terminal of the relay whenregister B was set on its fourth off-normal contact. There may be inpractice a number of ofiices all having the common first digit 3.Ordinarily, only a few of these ofiices will have the digit 4 as thesecond digit, and the translating switch will now be further advanceduntil the wiper 436 encounters the first bank contact cross connected tothe No. 4 battery tap.

Upon the receipt of the third digit and the setting of the register C inthe manner hereinbefore described, the output control switch includesrelay 445 in series with relays 443 and 444 through contacts of thetransfer relay 446, whereupon relay 445 operates and connects up testrelay 440. The conductor now connected to the right hand terminal oftest relay 440 has previously been connected'to the No. 2 battery tap bythe wiper of the C register upon the response of this register to thethird ofiice digit 2. As a result, relay 440 operates and causes afurther stepping action of the translator switch TS until the wipers431-437 arrive upon the bank contact set 342 shown in the drawings. Inthis position only, the potentials supplied to the left hand terminalsof the rela 440-442 are, respectively, the same as t e potentialssupplied to the right hand terminals of the relays, and no one of thethree test relays can operate. Under this condition no further advanceof the translator switch takes place and the stiflly adjusted transferrelay 446 operates due to the failure of stepping relay 439 tooperate.It will be noted that the circuit of relay 446 is prepared upon theoperation of relay 445, at the end of the registration of the thirdoflice digit, and that the circuit of relay 446 is closed each time thestepping relay 439 is deenergized; Relay 446, being stifiiy adjusted,does not operate until/rela 439 remains deenergized for an apprecia lelength of time. Upon operating, relay 446 locks itself to the groundedbank of wiper 411 at its upper armature, at the same time opening thecircuit of relays 443-445, whereupon these relays fall back anddisconnect the test relays 440-442. At its lower armature relay 446extends ground over start conductor 447 to relay 407 of the impulsegenerating relays 406 and 407 so as to start the retransmission ofimpulses.

When ground is placed on start conductor 447, relay 407 energizes andcloses a circuit for relay 406, at the same time placing ground onimpulse conductor 448. Relay 406 energizes and opens the circuit ofrelay 407, with the result that relay 407 shortly falls back and opensthe circuit of relay 406 and removes ground from impulse conductor 448.Relay 406 falls back and recloses the circuit of relay 407, whereuponrelay 407 operates again. This operation continues in this manneras longas there is a ground potential on start conductor 447. The copper collaron the core of relay 407, as indicated by the black upper portion of therelay core, is placed on the armature end of rather than on the heel endof the relay so as to render the relay slightly slow to operate, inaddition to being slow to release. The operation may be further variedby giving relay 406 a relatively stifi adjustment so that it will notoperate until the core becomes practically fully magnetized responsiveto its circuit being closed. I

Each time ground is placed on impulse conductor 448 impulse-correctingrelays 408 and 409 energize in series. Relay 408, being lightlyadjusted, operates first and closes a locking circuit for itself and forrelay 409 at its lower armature, and at its u per armature it preparesto ground impu se conductor 303. When relay 409 operates, shortly afterrelay 408 operates, it com letes the grounding of conductor 303 at itsupper the relay armature; short circuits relay 408 at its lowerarmature; and at its inner upper armature itcloses a circuit for its twowindings in series. The closure of this circuit is without immediateeffect, however, owing to the fact that the upper winding of relay 409is short circuited through the lower contacts thereof by the groundpotential on conductor 448. After it is short circuited at the lowercontacts of relay 409, relay 408 receives no current from the circuitincluding the exchange battery, but there is a circulating current setup through itswinding and through the lower contact of relay 409 due tothe receding magnetism in its core, which renders the relay slow torelease as is well known. As-

suming first that the impulse delivered by relay 407 .over conductor 448to relays 408 and 409 is shorter than a standard impulse, relay 407falls back before relay 408 falls back, but relay 409 remains operatedthrough the-lower contacts of relay 408 until relay 408 falls back,maintaining the ground potential on impulse conductor 303. If, on theother hand, the impulse delivered by relay 408 is longer than a standardimpulse, relay 408 falls back while relay 407 is still operated, andrelay 409 remains operated through the lower armature of relay 407 forthe duration of the impulse. In any case, relay 408 falls back,following its short circuiting at the lower contacts of relay 409, aftera suflicient time has elapsed to transmit an impulse of standard lengthover conductor 303. When it falls back, relay 408 terminates the impulseat its upper armature, and at its lower armature it removes ground fromimpulse conductor 448.

When the ground potentlal is removed from impulse conductor 448 at thelast point, either at relay 407 or 408 depending upon the adjustment ofrelays 406 and 407, the short circuit is removed fromthe upperwindinglays 408 and 409 is repeated each time a ground potential isplaced on impulse conductor 448.

It is to be noted that the impulses delivered by relay 408 will beindependent of ,reasonable variations in the potential of the exchangebattery owing to the fact that relay 409 is adjusted to operate when thecurrent flow through its windings reaches a predetermined value. .If thepotential of the exchange battery is high, this predetermined value isreached more quickly and relay 409 operates sooner following the closureof the circuit through relay 408 and the lower.

winding of relay 409, whereas if the voltage of the exchange battery islow relay 409 does not operate so quickly, but waits until the currentvalue through the circuit of the two relays reaches the same point asbefore. It will be understoodof course that in either case relay 409operates within a very small fraction of a second in the embodimentherein disclosed. It will be noted further that the variation in thetime required for relay 409 to operate does not afiect the length of theimpulse delivered over conductor 303, because, while-the circuit isprepared by relay 408, it is not completed until relay 409 operates toshort circuit relay 408 and the circuit over conductor 303 alwaysremains closed until relay 408 falls back responsive to being shortcircuited.

Return nowto the point at which the impulses begin to be placed upon theimpulse conductor 303. Responsive to the first impulse on thisconductor, operatingmagnet 316 of the sending switch Fig. 3 operatesthrough contacts of stop relay 314 and, upon subsequently deenergizingwhen the 1mpulse is terminated, advances the wiper 317 and 318 one step.Although, at its left hand contacts, operating magnet 316 opens thebridge across the outgoing impulse conductors 214 and 215, there is asubstitute bridge at this time closed through the upper contacts ofpick-up relay 313. Upon each succeeding impulse, magnet 316 operatesagain and advances the wipers 317 and 318 one'step upon deenergizing atthe end of the impulse. Upon the first step'of the wipers 317 and 318,Wiper 317 encounters a grounded bank contact, closing a circuit forpick-up relay 313. Relay 313 prepares the outgoing impulse circuit byremoving the local shunt at its upper contacts, while at its innercontacts it closes a circuit through contacts of stop relay 314 and overconductor 301 for the operating magnet 403 of the output control switch,Fig.4. Magnet 403 operates and prepares to'advance the wipers-404 and405 when it subsequently de-energizes.

With pick up relay 313 operated, each operation of magnet 316 results inan opening of the bridge across conductors 214 and 215, each suchinterruption being termed an impulse.

Referring now to the cross connections at the IDF, Fig; 4 it will benoted that the bank contact on which the first-digit wiper 431 of thetranslating switch is standing is cross connected to the sixth batterytap. This connection predetermines that the first digit transmitted willbe the digit 6.

At the end of the first impulse transmitted over conductors 214 and 215at the left hand contacts of operating magnet 316, the test wiper 318 isadvanced one step to the No. 2 batterytap. By this arrangement, if thedigit to be terminated is the digit 1,-current of the correct polarityflows through the polarized test relay 315 operating the relay toterminate the digit. In the present case, how.- ever, the digit to besent is 6 and the potential placed on the left hand terminal of thepolarized test relay 315 is the potent1al of the sixth battery tapcausing current to flow through the polarized relay in the directionopposite to that in which it must flow in order to operate the relay.This current flow is over a circuit path including the lower contacts ofstop relay 314, conductor 305, wiper 405 of the output control switch,wiper 431 of the translating switch TS, the bank contact on which it isstanding, and the associated jumper on the intermediate distributingframe IDF to the No. 6 battery tap. Upon the next step of the wipers ofthe sending switch, wiper 318 encounters the No. 3 battery tap,whereupon a current flow 1n the same direction as before, but of alessened intensity flows through the test relay. The

operation continues in this manner. until wiper 318 encounters the No. 6battery tap at the end of the fifth transmitted impulse,a-t which timeno current flows through the polarized test relay due to the fact thatit is connected to the same battery tap at both terminals. However, uponthe next step of the wipers, wiper 318 encounters the No. 7 battery tap,whereupon the current of the correct polarity flows between the No. 7and the No. 6 battery tap through the polarized test relay over thecircuit path above traced. The polarized test relay 315 now operates andcloses a circuit for stop relay 314, whereupon stop relay 314 operatesto terminate the digit. At its upper contacts, relay 314 places a shortcircuit across conductors 214 and 215; at its lower armature itdisconnects conductor 305 from the polarized test relay 315 andtransfers it to the polarized skip relay 311; at its inner upperarmature it opens the impulsecircuit of magnet 316 and closes itsrestoring circuit through its self-interrupting contacts and wiper 317and at its middle upper armature it opens the circuit over conductor 301of operating magnet 405 of the output control switch and closes alocking circuit for itself. When this occurs, magnet 403 falls back andadvances the wipers 404 and 405 one step, preparatory to the correcttermination of the next transmitted digit.

Skip relay 311 does not operate at this time from conductor 305 owing tothe direction in which it is polarized. The operating magnet 316 of thesending switch now buzzes rapidly under the control of the localinterrupter contacts and advances the wipers 317 and 318 to their normalpositions, whereupon the buzzing action stops due to the fact that wiper317 encounters an ungrounded contact in its normal position. At thistime the circuit of pick up relay 313 is opened, and

or to the tenth battery tap, predetermining that the next digit will bethe digit'O, corresponding to ten impulses. It will be understood ofcourse that the value of the various code digits may be assignedarbitrarily at the IDF in order to fit the trunking systerm that existsfrom the calling ofiice to the called oflice. Since the IDF connectionis to the tenth battery tap, the sending switch of Fig. 3 continues tooperate without reversing the current fiow through the polarized testrelay 315 until wiper 318 lands u on the contact connected to theeleventh attery tap, after the tenth impulse has been sent out. Whenthis occurs, relay 315 operates and terminates the. digit in thepreviously described manner.

The advance of the output control switch 1 from its second to its thirdposition takes place in the manner described above, whereupon wiper 405renders effective the third code wiper 433 of the translating switch.Since this wiper is standing on a bank contact cross connected to theseventh battery tap, the sending switch of Fig. 3 sends out the codedigit 7, whereupon the output control switch is advanced another step.

When the output control switch advances at the end of the third digit,wiper 405 engages the bank contact connected to wiper 434 of thetranslating switch whose present associated bank contact is crossconnected to the ski conductor, or the grounded pole of the exe angebattery. The advance of the output control switch, it will beremembered, occurs just at the end of the digit and responsive to theoperation of stop relay 314. It will be recalled also that relay 314 atits lower armature disconnects the sending control conductor 305 fromtest relay 315 and connects it instead to the polarized skip relay 311.The upper terminal of the skip relay is connected to the No. 1 batterytap and the relay is polarized so that it will operate only when thelower terminal is grounded, the connection to any battery tap of a morenegative polarity serving merely to send current through the skip relayin the reverse di- .interrupting contacts of the operating magnet of theoutput control switch for advancing the output control switch throughthe remaining code-digit position. It will be noted that the outputcontrol switch ma be advanced throughtwo or inore code positions,provided the corresponding contacts in the bank of the translatingswitch are connected to the grounded terminal of the exchange battery. vUpon being advanced through the fourth position, wiper 405, in its fifthposition, extendsthe-contml conductor 305 to the wiper of the-thousandsregister of Fig. 3. Ordinarily, the calling subscriber dials thecomplete number without hesitation, in which case the thousands registeris operated before the code digits have been sent out, and theretransmitting operation does not catch up with the registeringoperation. However, in case the callin subscriber has hesitated and hasnot yet dialled the thousands digit,-

the sending operation is held up because, the

stop relay 314 is maintained energized, after pick u relay 313. fallsback over a circuit through wiper of the thousands register by potentialsupplied through skip relay 311 from the No. 1 conductor to the wiper ofthe thousands register through the lower armature, oper ated, of stoprelay 314 and over conductor 305 and wiper 405 of the output controlswitch. In this case, the stop relay remains energized and holds up thetesting operation until the thousands register is operated. Since theoutput control switch has advanced beyond the influence of skip relay311, it is immaterial whether this relay'responds or not.

Assuming now that the subscriber has dialled the number withouthesitation, the sending operation continues and the thousands digit isterminated in accordance with the setting of the wiper of the thousandsregister to which the left hand terminal of the polarized test relay 315is connected after stop relay 314 falls back.

The usual advance of the output control switch takes place following thetermination of the thousands digit, whereupon the hundreds,-tens, andunits digits are retransmitted in the same manner.

When the output control switch advances another step at the end of theunits digit, wiper 405'encounters its last bank contact, placing apotential on conductor 212 which is obtained over conductor 305 throughcontacts of stop relay 314 from the No. 1 battery tap and through skiprelay 311. The placing of this potential on conductor 212 closes acircuit through wiper 208 of the register selector RSS and throughcontacts of relays 206 and 204 for switching relay 205 of the trunkcircuit TC. Switching relay 205 operates and locks itself to thegrounded release trunk conductor 202 at its inner lower igit the firstcontact in the bank of the armature and at its upper and lower armaturesit disconnects conductors 201 and 203 from linerelay 204 and extendsthem to the corresponding conductors of the selector S, thereby placingthe maintenance of the established connection under direct control ofthe calling subscriber.

Relay 204 falls back responsive to its disconnection by relay 205 and itopens the circuit of slow acting relay 206. Relay 206 falls back after aslight interval and frees the register sender by disconnecting thewipers 208211 of the register-sender selector.

In the re ister sender, release relay 312 falls back w en the registersender is freed and it grounds release conductors 302, 304, and 306,causin the operated apparatus of the register sender to restore tonormal. The restoration to normal of the output control switch isaccomplished through the last contact in the bank-of wiper 404 and theselfinter rupting contacts of the operating magnet 403.

The restoration to normal of the input control switch is accomplished byrelease magnet 413'which operates from conductor 306 through theassociated ofi-normal conis grounded by relay 312 so as to insure theadvance of the output control switch to its second, third and fourthpositions in case of a premature release due to the calling sub scriberhanging up his receiver while the sending operation is in progress. Therelease of the in ut control switch results in wiper 411 opening thelocking circuit of relay 446, whereupon relay 446 ungrounds startconduct-or 447, permitting the relays 406-409 to cease their operation.

Now, when the first train of impulses, representing the digit 6, istransmitted to the selector S over conductors 214 and 215 from thesending switch, line relay 221 of the selector S falls back momentarilysix times. Each time it falls back, relay 221 shunts relay 222 byconnecting the lower winding of relay 223'in parallel with the windingof relay 222. It is to be noted that the upper winding of relay 223 isopen circuited at this time to permit the current flow to build upquickly in relay'223. Relay 222 is maintained operated while shunted byrelay 223 due to the circulating current through relay 222. Relay 223and magnet 226 operate in series.

Each time relay 221 reoperates,it removes the shunt from around .relay222, after replacing the upper winding of relay 223 in a circulatingcurrent in its upper winding.

"terrupter contacts.

Each time relay 221 releases again, vertical magnet 226 operates againand another current flow takes place through the lower winding of'relay223.

At the end of the vertical movement of the selector, wipers-229231 havebeen raised opposite the sixth level of bank contacts by the sixoperations of vertical magnet 226, and relay 223 shortly falls backowing to the cessation of the circulating current in its upper winding,starting the hunting of the selector. The circuits are prepared forhunting action of the selector upon the first ofi-normal movement of theselector when relay 224 operates through the contacts of the operatedrelay 223, the associated oil-normal contacts, and

/ the interrupter contacts of i'otary magnet 2 28.

Relay 224 looks itself to release trunk con- .ductor 202 at its upperarmature and prepares a circuit for rotary magnet 228 at its lowerarmatures. Then, when relay 223 falls back at the end of the verticalmovement, the prepared circuit of the rotarymagnet is closed whereuponthe rotary magnet operates, advancing the wipers 229-231 one step intoengagement with the first set of bank contacts in the sixth level. Nearthe end of its stroke, magnet 228 opens its interrupter contacts,whereuponstepping relay 224 falls back and opens its own locking circuitand the rotary ma net circuit. The rotary magnet now falls bac andcloses its interrupter contacts again.

The further operation of the selector depends upon whether the trunkline terminating in the first set ofbank contacts is busy or idle. Ifthe first set of contacts tests idle,

- switching relay 225 now operates, seizing the connected trunk line. Ifthe first set tests busy, relay 225 is short circuited by the groundpotential encountered on the busy test contact by test wiper 230 anddoes not operate. This same ground potential is extended through theofl-normal contacts of the selector and the interrupter contacts ofrotary magnet 228 to stepping relay 224, which relay operates and causesa further advance by closing the rotary-magnet circuit.

This alternate operation of rotary magnet 228- and stepping relay 224continues until an idle trunk line is reached. It will be assumed thatthe trunk line comprising conductors 232234 s found to be idle and istherefore seized. When this trunk line is reached, switching relay 225is not short circuited and it operates from the grounded release trunkconductor 202 in series with stepping relay 224 through the associatedoil-normal and in- Relay 224 does not operate in series with relay 225owing to the rela-' tively high resistance ofthe latter. Upon operating,relay 225 opens the vertical magnet operating circuit and a point in therelease magnet circuit at its inner lower contacts,

leaving relay 222 energized through contacts of relay 221 and the upperwinding of relay 223. At its inner upper contacts, opens a point in thetest circuit and connects wiper 230 to the rounded release trunkconductor 202, thereby making the seized trunk busy immediately. At itsupper and lower armatures, relay 225 disconnects the incoming talkingconductors from relay 221 and extends them through wipers 229 and 23land the bank contacts on which they are standing to conductors 232 and234 respectively of the seized trunk line. The line relay of the seizedctrunk line (not shown) now operates and causes the associated releasetrunk conductor 233 to be grounded in the usual manner so as to hold upthe connection from the seized trunk line. Line relay 221 falls backresponsive to being disconnected by-relay 225, and places the lowerwinding of relay 223 in shunt of the winding of relay 222, at the sametime opening the initial energizin circuit of relay 222. Since thelocking circuit of relay 222 is now open at the inner lower contacts ofrelay 225, no further current flows through this relay from the exchangebattery, but the relay does not fall back immediately due to thecirculating current through its winding in series with the lower windingof relay 223. After an interval, relay 222 falls back and prepares a.circuit for the release magnet at its lower armature, removing oneground connection from conductor 202 at its upper armature.

relay 225 v Responsive to the remaining trains ofimtion may take placeas desired. The connection is. released in the usual manner when thereceivers are replaced upon the termination of the conversation.

The releaseof the selector S takes place responsive to the removal ofthe ground potential from release trunk conductor 233 of the trunk line,which results in the deenergization of switching relay 205 of the trunkcircuit TC and in the deenergization of switching-relay 225 of theselector S. When relay 225 falls back it closes at its inner lowercontacts a circuit through the lower armature of relay 222 and theassociated off-normal contacts for release magnet 227, the operatingcurrent being obtained from the lower winding of relay 223 through thenormally closed contacts of line relay 221. The release magnet 227 andrelay 223 operate over this circuit, but relay 222 does not operateowing to the relativelylow resistance of relay 223. Relay 223 closes acircuit through the associated oil-normal contacts and interruptercontacts for relay 224, which operate and extends this operating groundpotential to release trunk conductor 202, thereby noted that the spareset of guarding the selector during the releasing operation. When thenormal position is reached, the release magnet and relays 223 and 224fall back. Relay 224 ungrounds conductor 202.

Referring now again to Fi 4 it will be bank contacts shown in the bankof the wipers 431-437 of the translator switch TS has one contact (thecontact in the bank of wiper 437 associated with the A register, Fig. 3)connected to the unded terminal of the exchange battery. ince no contactofv the A register is connected to the grounded terminal of the exchangebattery, it is impossible for the translating switch TS to stop on thisset of bank contacts because no setting of the A register will satisfythe required condition for stopping because there will be a potentialdifference across test relay 442 regardless of which osition theregisterA is set in. Spare sets, it will be understood, may exist when there arefewer ofiices in the system than there are sets of contacts in the bankof the translator switch.

It will be noted that the upper set of contacts shown in connection withthe translator switch is labelled, Unassigned-ofiice set. This set ofcontacts is reserved for disposing of calls wherein the setting of theA, B, and C registers, Fig. 3, does not correspond to any assignedofiice. The contact in this set which is wiped over by the test wiper437 associated with test relay 442 is connected to the grounded terminalof the exchange battery so as to prevent the translating switch fromstopping on the unassigned-ofiice set. The relays 401 and 402 areprovided to dispose of the call when the unassigned-ofiice set has beenpassed over the second time. If the setting of the A, B, and C registersis in accordance with any assigned ofiice, the translating switch willstop without making more than a single complete revolution.

In this connection, it will be recalled that relay 443 is operated toconnect wiper 437 of the translator switch with the wiper of register Aby way of test relay 442 at the end of the dialling of the first ofiicedigit. It will be recalled also that, when this occurs, relay 442controls the operating magnet 438 through the medium of stepping relay439 to cause an advance of the wipers 431-437 until test wiper 437encounters the same potential on which the wiper of register A has beenset. When register B has been set, relay 444 is operated to complete aconnection between the wiper of register B and the wiper 436 of thetranslator switch, whereupon the wipers of the translator switch TS arefurther advanced under the joint control of test relays 441 and 442until a contactset is encountered in which the connections agree withthe responsive potentials on which the wipers of registers A and B thecontrol of all three test lelays 440-442. 1

It will be understood, of course, that the translator switch TS willnever advance beyond the set of contacts assigned to the called ofiiceas indicated by the setting of registers A, B, and C, because theadvance'of the translator switch stops in any case when the potential orpotentials encountered by the active testwiper or test wipers of thetranslator switchagree with the potentials preyiously connected up bythe ones of the reg-' lsters A, B, and C that have been set. If there isonly one assigned existing ofiice in the group of a possible one hundredoffi'ces indicated by the first digit dialled, relay 442 alone willdrive the translating switch until the contact group assigned to thisofiice is reached, and no further advance will take place responsive torelays 441 and 440 being connected up. Similarly, if the contact set towhich the wipers of the translator switch have been driven in twosuccessive movements under the control, first of relay 442 and thenunder the control of relays 442 and 441, is the only set correspondingto the first two oifice digits which have been dialled, then no furtheradvance of the translating switch takes place when relay 440 isconnected up, because the contact then engaged by wiper 435 is crossconnected on the intermediate distributing frame IDF to the samepotential which is encountered by the wiper of register C when it isproperly set in accordance. to the digit assigned to the single oflicein the tens group indexed by the instant setting of registers A and B.

It is only when the registers A, B, and C of Fig. 3 are incorrectly set,so that their setting does not correspond to the digits of any assignedofiice that the test wipers 437, 436, and 435 are unable to locate thesame combination of potentials on a contact set, and the switch makesmore than one complete revolution.

If the switch makes more than one revolution and therefore passes theunassignedin the special switch-through circuit at its lower armature.At its upper armature relay 402 operates relay 401 from the groundedrelease trunk conductor 212, whereupon relay 401 locks itself toconductor 212 and opens a point in the circuit of relay 402, at the sametime preparing the special-switch through circuit. lVhen the wiper 431passes oil the bank contact in uestion,.the circuit of relay 402 isopened w ereupon relay 402 falls back and opens a further point in itsown circuit, leaving relay 401 locked up to conductor 213.

When the upper contact of the unassignedofiice set is again groundedupon the next passage of wiper 431, the ground potential fails tooperate relay 402, because relay 401 is operated, and a circuit isclosed through contacts of the non-operated relay 402 and throughcontacts of the operated relay 401 and over conductor 212 as abovetraced to the switch-through relay 205 in the trunk circuit TC. Relay205 operates and switches the connection through, cutting 01f relay 204,which releases relay 206 to free the register sender.

It will be apparent that the above switchthrough operation takes placewith the selector S non-operated because no digits can be sent out inany case until after the translating switch TS has completed itsoperation. Under this condition, the incoming conductors 201 and 203 areextended through to line relay 221 of the selector S, which line relayis ordinarily disconnected by the usual operation of the selector beforethe switching relay 205 operates. In this case, a special tone from thetone source through the transformer 212 is placed on the calling linethrough the lower winding of relay 221, informing the calling subscriberthat the number is unobtainable and that he mustreplace his receiver andtry again.

In order to prevent the possible completion of the connection to asubscribers line in case the calling subscriber should disregard thetone and continue to dial, the operating circuit of the vertical magnet226 is opened at the upper contacts of relay 205 so as to prevent thevertical magnet from responding to deenergizations of line relay 221.The connection to the selector is released when the calling subscriberreplaces his receiver.

Referring now particularly to Figs. 1 and 2, the modified trunkingarrangement will now be explained. This arran 'ement can be understoodbest perhaps if reference is had to the Patent 1,633,118 granted June21, 1927 to McElyea. By way of explanation, it may be pointed out that aswitch such as S of Fig. 2 has its bank contacts arranged in tenhorizontal rows or levels, ten sets of contacts per level. It is commonpractice in manufacturing and in installing these switches to installthe switches in groups of ten, each group being called a shelf, therebeing a multiple from each contact in the bank of one switch to thecorresponding contacts of adjacent switches, a connecting rack isprovided comlnon to a plurality of shelves and a'cable known as a bankcable is run from each switch shelf to the frame. This cable contains asmany wires as there are contacts in a switch bank. Each shelf isrepresented on the connecting frame by a set of contacts, to which thecorresponding bank-cable wires are connected, and as many shelves asdesired are multipled together as regards their several levels and areappropriately connected to trunk cables representing trunks extending tothe next order of local switches or to inter oiiice trunk lines as thecase may be.

\ In case there are ten similar trunk groups accessible to a group ofselectors, the grouping is fairly simple, as the banks of ten shelvesmay be multipled together and connected to ten groups of outgoing trunklines, one group per level. In this case there are 100 switches involvedand there are 100 outgoing trunks.

Assume now that the traflic on one level of the group of selectors isslightly heavier than the traffic on any one of the other levels, theten trunks carrying the load from that one level may become overloaded,in which case it is necessary to rearrange the multipling so that tentrunks will carry the load of possibly 8 or 9 shelves as regards thelevel in question. If the traflic were still heavier on the level inquestion ten trunk lines might be able to handle trafiic from only threeor four shelves. Under such circumstances, with the level load as heavyas assumed, the addition of the traflic of another shelf onto a trunkgroup increases the total number of calls delivered into the group quitematerially, and it is diiiicult to secure a fine distribution of thetraflic in order to keep each trunk group working eificiently withoutbeing overloaded.

It may be pointed out that the condition such as outlined above ofabnormally heavy traffic per shelf, per trunk group is rarelyencountered when ten full levels of a group of selectors is working,because in that case the calls are ordinarily distributed more or lessevenly over the various levels of the shelves, with the result that alevel of a large number of shelves can be multipled together to sendtraflic into a group of ten trunks as above outlined. In case, however,there are only a small number of groups of trunks accessible to a,selector, two for example, a given shelf of switches will sendapproximately half the trafiio into a given trunk group if the calls areequally divided and more than half its traffic in one case if thetrafiic to that trunk group is heavier. The same condition obtains butto a lessening degree as the number of trunk groups per selector groupis increased from two up toward the full numeflicient use of the outsidecable system rather than from the standpoint of the economy of switching.equipment. Now, if the register senders could be arranged to send theircalls systematically to all levels of a selector group having only twogroups of trunks outgoing therefrom, half the levels could be multipledinto one group and half the levels into another group with the resultthat a fine distribu' 'tion of trafiie could be obtained.

The grouping of Figs. 1 and 2 is made under the assumption that thereare only two trunk groups accessible to the first selectors in theoflice in which the equpiment shown is located. Of these groups, the oneincluding the trunk comprising conductors 232234; is an outgoing group,while the roup includin the trunk comprising con uctors 235 237 isassumed to lead to local thousands se- 'lectors. Assuming that the localtrafiic is substantially equal to the outgoing traflic, the calls willbe fairly equally divided between the two groups. The outgoing group isarranged to receive traflic from the upper five levels of the selectors,while the localgroup is arranged to receive traflic from the lower fivelevels.- In order to direct the trafiie into the various levels, the reister senders are arranged to send out the igit 6 if the call isoutgoing and to send out the digit 1 if the call is a local call. Inorder to complete the distribution, the wi ers of the several switcheson a given shel for example, shelf 1 of Fig. 1, are set in variouspositions. For example, the wipers of selectors 1 and 2 of Fig. 1 havetheir wipers set in the normal way, one-step below the lower bank level;

the wipers of selectors 3 and 4 of this shelf are set opposite the firstlevel; the wipers of selectors 5 and 6 are set opposite the secondlevel; the wipers of selectors 7 and 8 are set opposite the third level;and the wipers of selectors 9 and 10 are set opposite the fourth level.As a result, when the digit 1 is sent, the selector used may be operatedto connect with a trunk line in any one of the lower five levels,depending upon the selector used, while if the digit 6 is sent theselector used may connect with any one of the upper five levels,depending upon which selector is used. It will be seen, therefore, thatthe trafiic from two selectors of the shelf of ten is sent out on eachof the upper five levels to the outgoing group and sent out on each ofthe lower five levels to the local group. The trafiic therefore has beenreduced to small another sub-group of ten trunks (S2) receives trafiicfrom the lower five levels of shelf 1 and from levels 4 and 5 of shelf2. The third sub-group of ten trunks (S3) receives traific fromlevels 6,7, and 8 of shelf 2, and there is a jumper extending down from thistrunk group indicating that it receives traific from four shelf levelsof the next shelf of the series. The same is true for the sub-group S4.From this it will be seen that either the local group (comprisingsub-groups S2, S4, etc.) or (comprising sub-groups S1, S3,-etc.) canhandle more than half of the total traflic but this is ordinarilynecessary, due to the fact that the peak load on the outgoing group andthe peak load on the local group do not ordinarily occur simultaneously.

If calculations or observations show that the formed groups of trunkscan handle more traflic thanis being directed to them or that they areoverloaded, the jumpering can be suitably rearranged and the adjustmentcan be finely made due to the relatively small traflic per shelf leveloffered by the improved arrangement hereinbefore presented.

As an alternative way of handling the sit- 1 stead of the staggeredarrangement 1 lus- 1 trated and an approximately equal distribution oftralfic could be made by dividing the register senders into five groups.The register senders in group #1 would send trafiic out over the firstand sixth levels by merely retransmitting the digits 1 and 6, as all thedirectors do in the arrangement above described; the register senders ingroup 2 would send out the digits 2 and 7 instead; the register sendersin group?) would send out the digits 3 and 8; and so forth.

Although the arrangement of Fig. 1 has been described as of particularutility in connection with a multi-office telephone system employingregister senders, this arrangement may often be used to advantage inother systerns not containing register senders. For example, in a2000-line system the first selectors are thousands selectors. Now, ifthe digits 1 and 6 are assigned to the two thousand-line groups,respectively, the calls will be scattered throughout the ten levels ofthe selectors provided the wipers are readjusted Fig.

It is to be understood of course that the arrangement is not limited tothe first se lectors but may be applied to any order of selcctors as theoccasion may arise.

It is to be understood that, although the arrangement has been describedin detail in connection with selectors having only two out-going trunkgroups accessible thereto, the same arrangement may be applied toselector groups having any number of outgoing trunk groups up to five.For example, if there are five trunk groups accessible to a group ofselectors the first five switches may have their wipers set in thenormal way one step below the first level of contacts, while the secondfive switches of the shelf have their wipers standing just below thesecond level of bank contacts. In this case the digits assigned to theoutgoing trunk roups are the digits 1, 3, 5, 7 and 9. The first fiveswitches on the shelf send their traffic out over the levels 1, 3, 5, 7,and 9, while the remaining switches send their traffic out over thelevels 2, 4t, 6, 8, and 10. As an alternative arrangement,

' the wipers of the second five switches of the shelf 10 may be set justbelow the sixth level instead of just below the second level, in whichcase the digits assigned to five outgoing groups are the digits 1-5,respectively. This results in the first five switches sending theirtrafiic out over the first five levels of the bank and in the last fiveswitches sending their trafiic out over the upper five levels of to thesame trunk group; likewisefl and 7,

a the bank. In this case levels 1 and 6 belong etc.

As an arrangement alternative to the one shown in Fig. 1, the digits 1and 2 may be assigned instead of the digits 1 and 6. In this latter casethe wipers of the selectors of a shelf are set as follows: switches 1and 2 below the first level, 3 and 4 below the third level, 5 and 6below the fifth level, 7 and 8' below the seventh level, and 9 and 0below the ninth level. In this case, when the digit 1 is dialled thecall may be sent out over either of the odd-numbered levels, while ifthe digit 2 is dialled the call may pass out over any one of theeven-numbered levels, depending upon which switch handles the call.

Referring again to the impulse-correcting device shown in Fig. 4 andcomprising relays 408 and 409, it will be apparent that, although thisis shown in connection with an arrangement for transmitting impulses to'the sending switch of a register sender, it is readily applicable toimpulse repeaters used in trunk lines to repeat impulses from onesection to another andthat its impulse sending contacts may be suitablyrearranged to send interruptions of a fixed length rather than closedimpulses of a fixed length.

What is claimed is:

1. In a translating register sender for use in multi-oflice telephonesystems, ofiice registers for registering the oflice digits,respectively, of telephone numbers, a wiper and a bank of contacts foreach oflice register, multiple connections between the respective bankcontacts of said oflice registers, a translating switch, and means forsetting said translator switch in accordance with the composite settingof said ofiice registers, said means being controlled through saidwipers and said multiple connections.

2. In a register controller for use in telephone systems, a translatingswitch having a" plurality of test wipers, cooperating bank contactshaving a plurality of combinations of fixed test potentials thereon,testing apparatus controlled over said test wipers from said bankcontacts, and digit-registering apparatus arranged to predetermine thecombination of test potentials to which said testing apparatus willrespond.

3. In a register sender for use in telephone systems, a translatingswitch having a plurality of sets of wipers and cooperating test bankcontacts, said bank contact sets having fixed combinations of testpotentials thereon, means including testing means for advancing saidtranslating switch under the control of said test wipers and forstopping the switch with its test wipers in association with a bankcontact set having a predetermined combination of test potentialsthereon, and registering means for predetermining the combination oftest potentials to which said testing means will respond to stop saidswitch.

4. In a register-sender system for use in directing the calls in amulti-oflice telephone system, a plurality of register senders eachhaving a translating switch arranged to be set in accordance with theoffice-designating portion of called numbers, each of said translatingswitches having a plurality of test wipers and cooperating bank contactsfor controlling the setting of the associated translating switch and aplurality of digit wipers and cooperating bank contacts for controllingthe operation of the automatic switches, multiple connections betweenthe contacts in the bank of the test wipers of-the several translatingswitches, and separate multiple connections between the contacts in thebankof the digit wipers of the several translating switches.

5. In a multi-oflice telephone system, a plurality of register senderseach having a translating switch arranged to beset in accordance withthe otfice designating portion of called numbers, each of saidtranslating switches having a plurality of test wipers and cooperatingbank contacts for controlling the setting of the associated translatingswitch and a plurality of digit wipers and cooperating bank contacts forcontrolling the operation of the automatic switches, multipleconnections between the contacts in the bank Lesa-o of the test wipersof the several translating switches, separate multiple connections between the contacts in the bank of the digit wipers of the severaltranslating switches, and 5 means common to all of said translatorswitches whereat the test value of an contact set may be simultaneouslychange in all of said translator switches.

6. In a multi-oflice telephone system, a plurality of register senderseach having a translating switch arranged to be set in accordance withtne oflice designating portion of called numbers, each of saidtranslating switches having a lurality of test wipers, and cooperatingban contacts for controlling the setting of the associated translatingswitch and a plurality of digit wipers and cooperating bank contacts forcontrollin the operation of the automatic switches mu tiple connectionsbetween the contacts in the bank of the test wipers of the severaltranslating switches, separate multiple connections between the contactsin the bank of the digit wipers of the several translating switches, andmeans common to all of said translator switches whereat the test valueof any contact set may be simultaneously changed in all of saidtranslator switches, and whereat the digit value of any contact set maybe simulao taneously changed in all of said translator switches.

7. In combination, a plurality ofregistering-devices having wipers andbank contacts, and means for setting each device independas ent of anyother, a translating device having bank contacts and cooperating testwipers, multiple connections between the bank contacts of all saiddevices, and testing means controlled through said test wipers and testcontacts in accordance with the setting of said registering devices forstopping said translating device in a position individual to anycomposite setting of said registering devices. 8. In combination, aplurality of registering devices and means for setting each mdependentof any other, atranslator switch having test contacts and cooperatingtest wipers, testing means controlled through said test wipers and testcontacts in accordance with the setting of said registering devices forstopping said translating switch in a position individual to anycomposite setting of said registering devices, a plurality of othertranslating switches each having a plurality of controlling registerdevices associated therewith, and means whereby the position assigned inany translator switch to a given composite setting of the associatedregistering devices may be simultaneously altered.

9. In combination, a plurality of register switches and means forsetting each independent of the setting of any other one, a translatorswitch, testing means for stopping said translator switch in, a positionindiassociate vidual to any desired composite setting of said registers,a pluralit of other sets of register switches each set aving anassociate translator switch, and meanscommon to all said translatorswitches for assigning at will the position in which the translatorswitches will stop in accordance with any predetermined settin of therespective associated register switc es.

10. In combination, a plurality of register switches and means forsetting each mdependent of the setting of any other one, a translator.switch, testing means for stopping said translator switch in a positionindividual to any desired composite setting of said registers aplurality of other sets of register switches each set having anassociated translator switch, and means for simultaneously altering theposition in which the several translator switches will stop responsiveto a (particular setting of the respective re 'ster sets.

11. In com ination, a plurality of register switches and means forsetting them one after the other, a translator switch, means controlledb simultaneous testing means for settin sai translator switch in aosition indivldual to a composite setting 0 said registers, and meanswhereby the testing operat1on may be carried out in successive stages asthe several digits are registered one after the other.

12. In a register sender for use in a multioflice telephone system, atranslator switch of the type which rotates in a forward direction only,oflice registering apparatus for registering the oflice designation,means for taking a register sender or use and operating said translatorswitch under the control of the oflice' registering apparatus to aposition corresponding to the called ofiice, register-sender freeingmeans prepared for operation upon the translator switch reaching apredetermined position for the first time, and means for operating saidfreeing means to free said register sender and to give the callingsubscriber a special signal when the translator switch reaches the saidpredetermined position the second time responsive to the ofiiceregistering apparatus having been set in a position corresponding to anunassigned oiiice. r

13. In a register sender for use in telephone systems, a translatorswitch set under the control of a plurality of test wipers, and underthe control of a plurality of digit registers, contacts in the bank'ofsaid test wipers having predetermined test potentials thereoncorresponding to settings of said registers, and means for preventingsaid trans- 125 lator switch from stopping in one of its unassignedpositions by connecting a test contact of such position to a testpotential, which does not correspond to any possible setting of saidregisters.

14. In an impulse repeating device arranged to receive a continuousseries of impulses, a first relay arranged to operate and restoreresponsive to each incoming impulse, a second relay arranged to operateand restore responsive to each incoming impulse, contacts on the secondrelay for short circuiting the first relay, and an outgoing impulsecircuit controlled by the joint operation of the two relays each time anincoming impulse is received.

15. In an impulse repeating device, a first relay arranged to operateand restore responsive to each incoming impulse, a second relay arrangedto operate and restore responsive to each incoming impulse, contacts onthe second relay for short circuiting the first relay, an outgoingimpulse circuit, and contacts on said first relay effective each timethe first relay responds to an incoming impulse to send an impulse oversaid outgoing impulse circuit of a length dependent upon the timerequired for said first relay to restore responsive to being shortcircuited.

16. An impulse correcting repeater responsive to incoming impulses torepeat corrected outgoing impulses comprising two impulse receivingrelays connected in series, the second of said relays being stifilyadjusted relative to the first, whereby the first relay operates beforethe second, contacts on the second relay for shunting the first relay soas to bring about its deenergization. and an outgoing impulse circuitcontrolled by the two relays jointly.

17. An impulse correcting repeater responsive to incoming impulses torepeat corrected outgoing impulses comprising two impulse receivingrelays connected in series, the second of said relays being stifilyadiusted relative to the first, whereby the first relay operates beforethe second, contacts on the second relay for shunting the first relay soas to bring about its deenergization. and an outgoing impulse circuitcontrolled by the first relay.

18. An impulse repeating device for repeating corrected impulsescomprising two receiving relays with their windings connected in series,locking contacts on the first receiving relay for closing a lockingcircuit to maintain a current flow through the receiving relaysindependent of the sending source when the first relay responds to animpulse, contacts on the second relay for shunting the first relay tobring about its deenergization and an outgoing impulse circuitcontrolled by one of said relays.

19. An impulse repeating device for repeating corrected impulsescomprising two receiving relays with their windings connected in series,locking contacts on the first I receiving relay for closing a lockingcircuit to maintain a current flow through the receiving relaysindependent of the sending source when the first relay responds to animpulse, contacts on the second relay for shunting the first relay tobring about its deenergization, and means including a differentialwinding and locking contacts on the second relay for securing a quickdeenergization of the second relay at the termination of the incomingimpulse.

20. In an impulse-repeating electromagnetic device arranged to receiveimpulses over an incoming impulse conductor and to repeat such impulsesover an outgoing impulse conductor, means in said device responsive toeach incoming impulse to repeat an outgoing impulse of a fixed lengthregardless of the length of the incoming impulse, a current source forsupplying operating current to said device, said means being arranged sothat the repeated impulse is substantially independent of minorfluctuations in the E. M. F. of said current source.

21. In a telephone system wherein a register set is associated with atrunk line through the action of a register selector having a line relayand a switching relay, a circuit for said switching relay controlled bysaid line relay, and a setting circuit for the seized register setincluding contacts of said line relay and contacts of said switchingrelay, said switching relay being slow acting whereby it does not fallback responsive to series of impulses transmitted to said register setbut falls back responsive to a prolonged deenergization of the linerelay.

22. In a telephone system wherein registering devices are associatedwith a trunk line through the action of a register selector having'aline relay and a switching relay, a circuit for said switching relaycontrolled by a line relay in the trunk circuit, a setting circuit forthe registering apparatus of a seized registering device includingcontacts of said line relay and contacts of said switching relay, saidswitching relay being slow acting whereby it does not fall backresponsive to series of impulses transmitted to said register sets butfalls back responsive to a prolonged deenergization of the line relay, arelease trunk conductor, circuit arrangement associated therewithwhereby it is necessary to maintain said release trunk conductorcontinuously grounded, and'contacts on said line and switching relaysfor maintaining the ground potential on said release trunk conductor.

In witness whereof, I hereunto subscribe my name this 14th day of March,A. D. 1928.

JOHN I. BELLAMY.

